Blood oxygenation apparatus



Dec. 8, 1970 J. ROZHOLD ET AL 3,545,937

BLOOD OXYGENATION APPARATUS A: I

FiledJan. 31, 1967 United States Patent O 3,545,937 BLOOD OXYGENATION APPARATUS Jaroslav Rozhold and Zdenek Rozhold, Bratislava,

Czechoslovakia, assignors to Chirana Zavody vdravotnickej techniky, odborovy podnik, Stara Tura, Czechoslovakia Filed Jan. 31, 1967, Ser. No. 612,922

Claims priority, applicatitgggfieghoslovakia, Feb. 2, 1966,

Int. Cl. A61n 1/03 US. Cl. 23-258.5 3 Claims ABSTRACT OF THE DISCLOSURE Blood oxygenation apparatus in which blood flows sequentially through a normally vertical oxygenation conduit, a defoaming chamber at the upper end of the conduct, and a collection chamber partly separated from the defoaming chamber by a partition, but communicating therewith at the top and bottom of the partition, the conduit, chambers, and partition being formed by two plastic sheets welded along elongated seams. Blood and oxygen are mixed in a metallic inlet tube equipped with a perforated membrane, and are discharged separately from the collection chamber.

BACKGROUND OF THE INVENTION This invention relates to blood oxygenation apparatus, and particularly to apparatus in which the carbon dioxide in blood withdrawn from a patient is exchanged for oxygen, and the blood is thereafter returned to the patient.

It is known to disperse oxygen in venous blood in the form of fine bubbles providing a large gas-liquid interface so that oxygen is absorbed by the erythrocytes in the blood, and carbon dioxide is simultaneously removed from the blood and mixed with the gaseous oxygen. Conventional oxygenation apparatus operating in the manner described is made of stainless steel if it is to be used repeatedly, or of plastics if intended for a single application only.

The stainless steel devices require extensive disassembly cleaning, and reassembly between applications. The known plastic devices are ready for immediate use, but hold a large volume of liquid when intended for blood circulation at a high rate, and at least a major portion of the liquid needed for initially filling the apparatus must be blood obtained from a human donor. It would not be advisable to dilute the patients blood with artificial blood extenders in the large amounts needed.

SUMMARY The main portion of the blood oxygenation apparatus of this invention consists of two sheets of resilient plastic which are integrally bounded to each other along elongated seams or welds.

The welds define, in the space between the sheets, an oxygenation conduit which is elongated vertically in the normal operating position of the apparatus, a defoaming chamber, and a collection chamber. The defoaming chamber communicates with the normally upper end of 'the oxygenation conduit and extends transversely to a normally vertically extending partition which separates the defoaming and collection chambers but permits communication there'between at the upper and lower ends of the partition. The apparatus has a liquid outlet at the lower end of the collection chamber and a gas outlet communicating with the upper end of the collection chamber.

When made of suitable and readily available synthetic resin compositions or plastics, the apparatus of the inven- Patented Dec. 8, 1970 tion can be sterilized easily, and its sterility in storage is maintained without difliculty. It permits defoaming of the passing mixture of gas and blood in a chamber of relatively small volume so that the apparatus may safely be filled with artificial blood extender at the beginning of its operation.

The apparatus causes circulation in the fluids contained therein from the oxygenation chamber to the collection chamber as will presently become apparent, and thus can be operated without the use of external pumps.

Other features and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood from the following description of a preferred embodiment when considered in connection with the attached drawing.

BRIEF DESCRIPTION OF THE DRAWING The sole figure of the drawing shows an oxygenation apparatus of the invention in elevational section.

DESCRIPTION OF THE PREFERRED EMBODIMENT Two plastic sheets 10, of which only one is visible in the drawing are integrally bonded to each other by heat sealing or welding along narrow seams. The sheets and scams form a long normally vertical tube 6 into whose bottom end a metallic T-fitting 2 is inserted. The normally horizontal side arm 1 of the fitting forms a blood inlet for the apparatus. The bottom end of the fitting 2 carries a cap 3 having an inlet nipple 4 for oxygen. A membrane 5 of polyvinyl chloride and formed with a multiplicity of small perforations 5 is sealed between the fitting 2 and the cap 3.

The upper end of the tube 6 communicates with a large space between the sheets 10 which is partly divided into a defoaming chamber 7 laterally adjacent the tube 6 and a collection chamber 12 remote from the tube by a seam 11 which forms a partition permitting communication between the chambers at its top and bottom ends.

A multiplicity of relatively short polyamide fibers bunched into a porous sponge-like mass 8 occupy most of the defoaming chamber 7. The fibers are preferably of non-circular cross section which has been found to prevent matting. They are coated with a layer of a conventional silicone anti-foaming agent too thin to permit pictorial representation.

One of the plastic sheets 10 has a slit 9 near the top of the collection chamber 12 which is normally closed by the resiliency of the sheet material, but opens when the gas pressure within the chamber exceeds atmospheric pressure by a small amount. An outlet passage at the bottom of the collection chamber 12 sealingly receives an outlet tube 13 whose upper orifice is above the bottom end of the partition 11, but below the opening which connects the tube 6 to the chamber 7.

A horizontal channel 14 between the tops of the sheet 10 may receive a rod or bracket of a support from which the apparatus is suspended during use. Both ends of the channel are open to the atmosphere and it is sealed from the chambers 7, 12.

The afore-described apparatus is operated as follows:

When the inlet 1 is connected to the source of blood to be oxygenated, and the nipple 4 to a tank holding compressed oxygen, the gas pressure prevents blood flow downward through the perforations 5 in the membrane 5, and the column of blood above the membrane is mixed with fine bubbles of gas. The mixed fluid passes upward in the tube -6 in which the oxygenation of the blood takes place.

The mixture which enters the chamber 7 from the top of the tube 6 separates into its gaseous and liquid constituents upon contact with the large area of antifoarning agent on the surface of the fibrous mass 8, and the two phases pass separately into the collection chamber 12 above and below the partition 11.

Because of the location of the upper orifice of the outlet tube 13, the fiowing liquid is diverted upward after passing the partition 11, and residual gas bubbles are released before the oxygenated blood is discharged through the tube 13. The gas, which consists of excess oxygen and of carbon dioxide purged from the blood, is released through the slit 9.

The specific gravity of the mixture of blood and gas in the tube 6 is substantially lower than that of the blood in the outlet tube 13. Blood therefore flows through the apparatus without the use of an external pump, the necessary energy being provided by the gas admitted through the nipple 4. The flow stops if the tube 13 is not completely filled with blood.

The rate at which blood may be oxygenated in the apparatus depends only on the length of the oxygenation tube 6. The tube is initially made long enough to provide adequate oxygenation at highest flow rate of blood through the apparatus that is expected. If the apparatus is to be used at a lower flow rate, the plastic tube 6 may be shortened simply by cutting it. The volume of liquid in the apparatus may thus be limited to the minimum consistent with the intended fiow rate.

Even under conditions of maximum flow rate, the liquid capacity of the apparatus is so small that liquid blood substitutes may safely be employed for originally filling the apparatus, as is necessary.

The sheets may be made of polyvinyl chloride, but other plastics are known to be suitable for contact with blood and to be capable of being sterilized in a simple manner. While heat sealing of the sheets is the most conventent and economical method of forming seams there-I between, other seam-forming methods may be resorted to if the nature of the sheet material so requires.

It should be understood, therefore, that the foregoing disclosure related only to a preferred embodiment of the invention, and that it is intended to cover all changes and modifications of the example of the invention chosen for the purpose of the disclosure which do not constitute departures from the spirit and scope of the invention set forth in the appended claims.

What is claimed is:

1. An appaartus for oxygenating blood comprising (a) two plastic sheet members arranged in approximately parallel superposed relationship and bonded to each other along seams, said seams defining between said members:

(1) an oxygenation conduit elongated in a vertical direction in the normal operating position of the apparatus;

(2) a defoaming chamber communicating with the normally upper end of said conduit and ex tending therefrom transversely of said direction and containing a porous mass of plastic fibers consisting mainly of synthetic polyamide resin coated with an anti-foaming agent for separating said blood into substantially gaseous and liquid phases;

(3) a collection chamber communicating with said deformation remote from said conduit;

(4) a normally vertically extending partition separating the collection chamber from said defoaming chamber, said chambers communicating at the normally upper end and at the normallyllower end of said partition to receive respectively the gaseous and liquid phases therein;

(b) at least one of said sheet members consisting of resilient material and formed with a slit comprising a gas outlet means located at the upper end of said gas chamber, said slit being normally closed by the resiliency of said material and being opened by internal gas pressure in said collection chamber; and

(c) a liquid outlet at the normally lower end of said collection chamber.

2. An apparatus as set forth in claim 1, wherein said liquid outlet includes a tubular member having an orifice in said collection chamber above said lower end of the partition in said operating position of the apparatus.

3. An apparatus as set forth in claim 2, wherein said seams define an opening connecting said oxygenation tube to said defoaming chamber, said orifice being below said opening in said operating position.

References Cited UNITED STATES PATENTS 2,833,279 5/1958 Gollan "23-2585 3,112,746 12/1963 Gewecke et a1 23258.5

FOREIGN PATENTS 1,181,707 1/1959 France 23258.5

' JAMES H. TAYMAN, m, Primary Examiner US. Cl. X.R. -178; l28-214 

